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BUG: KASAN: use-after-free in __gtp_encap_destroy+0x194/0x1b0 drivers/net/gtp.c:359
Read of size 8 at addr ffff88806edaabd0 by task syz-executor.0/11406

CPU: 1 PID: 11406 Comm: syz-executor.0 Not tainted 5.11.0-rc5-next-20210128-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
 __kasan_report mm/kasan/report.c:399 [inline]
 kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
 __gtp_encap_destroy+0x194/0x1b0 drivers/net/gtp.c:359
 gtp_encap_destroy+0x16/0x20 drivers/net/gtp.c:373
 udp_destroy_sock+0x1e1/0x220 net/ipv4/udp.c:2580
 sk_common_release+0x64/0x390 net/core/sock.c:3256
 inet_release+0x12e/0x280 net/ipv4/af_inet.c:431
 __sock_release+0xcd/0x280 net/socket.c:599
 sock_close+0x18/0x20 net/socket.c:1258
 __fput+0x283/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x190 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x417b71
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a4 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffc07a0b180 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000417b71
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000004
RBP: 0000000000000001 R08: 00000000000017b5 R09: 00000000208517b9
R10: 00007ffc07a0b260 R11: 0000000000000293 R12: ffffffffffffffff
R13: 00000000000461f1 R14: 00000000000003e8 R15: 000000000119bf8c

Allocated by task 11408:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:403 [inline]
 ____kasan_kmalloc mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:406
 kmalloc_node include/linux/slab.h:579 [inline]
 kvmalloc_node+0x61/0xf0 mm/util.c:587
 kvmalloc include/linux/mm.h:785 [inline]
 kvzalloc include/linux/mm.h:793 [inline]
 alloc_netdev_mqs+0x97/0xea0 net/core/dev.c:10464
 rtnl_create_link+0x219/0xad0 net/core/rtnetlink.c:3171
 __rtnl_newlink+0xf9b/0x16e0 net/core/rtnetlink.c:3433
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:674
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2437
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 11408:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
 ____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:364
 kasan_slab_free include/linux/kasan.h:191 [inline]
 slab_free_hook mm/slub.c:1562 [inline]
 slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1600
 slab_free mm/slub.c:3161 [inline]
 kfree+0xe5/0x7b0 mm/slub.c:4202
 kvfree+0x42/0x50 mm/util.c:616
 netdev_freemem net/core/dev.c:10418 [inline]
 free_netdev+0x4a9/0x5e0 net/core/dev.c:10587
 __rtnl_newlink+0x1484/0x16e0 net/core/rtnetlink.c:3447
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:674
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2437
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88806edaa000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 3024 bytes inside of
 4096-byte region [ffff88806edaa000, ffff88806edab000)
The buggy address belongs to the page:
page:000000002c10bc83 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6eda8
head:000000002c10bc83 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head)
raw: 00fff00000010200 0000000000000000 0000000100000001 ffff88800fc42140
raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88806edaaa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806edaab00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88806edaab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88806edaac00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806edaac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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